Worldwar: Upsetting the Balance picks up where the second left off, with the revelation that the bomb in front of Moscow was indeed of Soviet manufacture, built with the plutonium they got from the Lizards' destroyed stockpile. Not long afterward the Germans follow with their own bomb, which they use to destroy a troop concentration near Breslau, and in retaliation the Lizards destroy Munich, setting up a policy that they will destroy a human city for every bomb humans use against them. Shortly thereafter the Americans destroy a troop concentration in Chicago, and in retaliation the city of Seattle is destroyed (although the Lizards briefly consider and then disregard Denver, not realizing that the secret bomb project is being carried out there).

All the plotlines that were established in the first two volumes continue to be developed and woven together in a manner that is really too complex to recount in a brief review. Some people have complained that the action sags in this book, but I found it so compelling that I stayed up until 2AM reading it, forgetting entirely about working on my thesis or anything else.